I'm not sure what you mean by "Hard" but if it's reving high adjust your idiling screw.
it basically lets the bike work at higher revs, for example on mine it gives it unlimited revs, so it wont stop at about 6000rpm like a normal bike but just keep going, it can be bad because if the revs get too high the engine may explode
The timing is off.
it could be due to the steper motor but i suggest you take it to mechanic because no saxo has ever had a carburetor
you are stepping on the gas peddle too hard
Fusion? Pulse? Revs? or my faviroute Hard Core?
check for vaccume leaks. this can sometimes be hard to do so take you time.
You may be pressing the gas pedal too hard
Governors limit the RPM on the engine. Removing it will allow higher revs but can cause harm to your engine.
It is time for a professional car mechanic to have a look. The steering may be caused by dry joints (needs greasing), the revs may need the engine to be adjusted to run slower.
check your vacume lines by spraying them down with carburetor cleaner. if the engine revs when you spray you found the leak. also check your air flow meter it could just be dirty.
If your vehical is a tracker and you just put the timing chains in, it was done wrong
When looking from the front of the car, on the right of the carburetor is a brass (could look almost black if covered in grease) knob about a cm in diameter. There is a spring along its length which should help identify it. Turn it as if you were screwing in a screw (could be clockwise or anticlockwise depending on how you look at it) to increase the idle revs and vice versa.